Usually the marking of information to be recorded on film, such as the identity information of a patient as well as necessary information relating to diagnosis, imaging process and filing, is performed manually or by using a separate device particularly designed for the purpose. When the markings are performed manually, the procedure may be e.g. such that the necessary information is written on an adhesive tape which is glued to the film after imaging. The markings can also be made in a manner that to the surface of a film cassette is glued a lead tape on which is written the information needed for X-ray imaging. Thus, the text written on a lead tape is projected on an X-ray film during the imaging process and becomes visible during the film development. A problem with these prior known manual marking methods is that they take a lot of time and they also involve a relatively high risk of error.
When using a prior known separate marking device, the information is first written on a piece of paper and the text is projected on a photographed, still nondeveloped X-ray film by means of a photoprojector included in the device. The latent marking information on the film can be made visible during development of the film. Such marking device is placed in a darkroom in connection with developing equipment which leads to a risk of marking information getting mixed up since the writing and marking of information take place in different locations.